>
>At 08:04 PM 10/13/1999 -0400, Phil Levin W2GE wrote:
>>
>>
>>I'm quoting without names a message from what our CB brethren are up to.
>>
>>
>>"Take for instance...
>>
>>
>>2X4CX15,000 being driven by 3X8877
>>Ep was close to 14 kV on the 15,000s....
>>
>>Power output was capable of over 80,000 watts Bird. Tuning it up, with
>>a 1 kW slug in the Bird meter for reverse measurements, we couldn't get it
>>to wiggle up to 40 kW forward output. At the 44 kW mark (or thereabouts),
>>we blew the top of the antenna off, a nice blue corona came, and the
>>antenna spit flames! Nice, to say the least. The tubes are run Class C,
and
>>tetrodes are the tube of choice. What with screen volts, you get better
>>efficiency. Just have to keep those grids biased WAY negative, and you
>>can live with the higher plate voltage.
>>
>>After that, we went to a "fighting stick" (Quarter wave, usually made
>>from
>>3/4 inch copper pipe, chrome plated) and we where able to tune the amp
>>to
>>75 kW. It still had more to go, but that was where we left it for a
>>competition. This was the inaugural run of the amp.
>>
>>You might wonder where the power comes from for one of these beasts (and
>>this is smallish. The last one that I saw perform (over 4th of July)
>>was
>>capable of nearly 125 kW Avg. output)).
>>
>Can we hope that the FCC will drop by a few of these competitions?
? Probably not Pete. There are too many things in the story that don't
add up. . Besides that, at a major 4th of July CB shootout, any dude who
showed up with a pair of 4CX15,000As would be totally embarrassed and
laughed at. . . For instance, at a shootout in July '97, some potato
farmer from Idaho had an 8973 that ran close to 22kV on the anode. He
had a 50A anode current meter that pegged out when he whistled in the
mic, so there was no way to tell how much input power he was actually
running. My guess is around 65A. The electric plant was a modified
Keith Black alcohol-burning dragster engine driving a surprisingly
compact General Electric three-phase, 2MW alternator. There was no HV
transformer, so the alternator was probably delivering around 16kVAC to
the FWB rectifiers. . The amplifier was operated in Class AB1. It was
driven by a 4CX1500B, also in Class AB1, driven by a TS-440S. . . This
design eliminated a 700kW modulation transformer for big weight savings
The farmer claimed that he made his own alcohol from Idaho potatos. He
was serving free samples mixed with iced tea, served in iced tea glasses.
. He had plenty of pitchers of the stuff to go around, and a big No
Smoking sign for laughs. . // The antenna was a hydraulically
operated, tilt-up halfwave made from 4 inch copper pipe. Needless to
say, there was no power meter at th
cheers, Pete.
- Rich..., 805.386.3734, www.vcnet.com/measures.
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